`#![doc = include_str!("../README.md")]` and links to crate items

Yandros has a nifty little trick for that. They just redefine the links they used in the README to point to the local item before adding the README to the docs. Like so. That way the external link is overridden in the local docs but still works in the README. You'd still have to maintain the external links though, which can be annoying for sure.